Vitamin C to reduce oxidative stress, more evidence

Older adults may be able to combat oxidative stress in their cells
that may damage tissues by loading up on vitamin C, claim American
researchers.

Older adults may be able to combat oxidative stress in their cells
that may damage tissues by loading up on vitamin C, claim American
researchers.

Scientists at the University of Colorado believe that oxidative
stress may have played a part in previous observations of reduced
resting metabolism in older adults.

Although virtually all living organisms on Earth need oxygen to
exist, oxygen can combine with other molecules to form toxic oxygen
"free radicals,"​ said CU-Boulder Research Associate
Christopher Bell of the kinesiology and applied physiology
department. "When oxygen mixes with the wrong crowd, it also can
be our enemy,"​ he continued.

Destructive molecules have been to shown to 'team-up' with
oxygen in the human body, resulting in oxidative stress, he said.
As we grow older, the effects of oxidative stress become greater.
Bell maintained that some scientists believe that by destroying
tissue, increased oxidative stress may contribute to many
age-related ailments of older people.

In 1998 and 2001, a group led by Assistant Research Professor
Pamela Parker Jones of the kinesiology and applied physiology
department published papers showing that older adults burn fewer
calories at rest than their younger counterparts. This was an
important finding, said Bell, demonstrating that more calories are
available to turn into fat in older adults.

In 2001, Jones' group also published a follow-up study showing
that the lower metabolic rate in older adults is due in part to a
decreased ability of the nervous system to support resting
metabolism. Jones' group believes this decline in neural support of
resting metabolism with age may be related to increased oxidative
stress.

In a new study, Bell is trying to remove the influence of
oxidative stress in older adults to find out if the resting
metabolism will be increased.

"We can combat the effects of oxygen free radicals by giving
older adults substances known as antioxidants,"​ said Bell.
"The body produces an abundance of antioxidants when we are
young, but as we age, the production goes down. This increases the
importance of healthy eating for older adults because foods such as
fruit and vegetables are rich in anti-oxidants."​

In preliminary experiments, Bell measured the resting metabolism
before and after an infusion of vitamin C directly into the veins
of older adults between 60 and 74 years old. The results show that
following vitamin C infusion, resting metabolism increases on
average by almost 100 calories per day, he said.

"It is possible that the removal of oxidative stress using
vitamin C could lead to a significant increase in resting
metabolism in these older adults,"​ said Jones. "This has
important implications for reducing age-associated weight
gain."​

In addition, higher resting metabolic rates have been linked
with a reduction in risks for cardiovascular and metabolic diseases
such as diabetes due to the favourable influence on body weight and
body fat, she said.

Jones said it was too soon to draw definitive conclusions from
the studies. But the vitamin C studies suggest older adults may be
able to avoid increased body fat and some of the associated
diseases by removing the unfavourable effects of free radicals and
increasing resting metabolism.